Object-forming machines (so-called 3D printers) configured to form a three-dimensional object have been known. The 3D printers are usually configured to laminate layers of an object material one by one in accordance with a design data to produce an object of a desired cross section.
When a certain degree of accuracy is required for an outer profile or an inner structure of the object formed using such a 3D printer, a dedicated apparatus has been used to measure an inner cross section of the formed object (see, for instance, Patent Literature 1: JP-A-2001-264047, Patent Literature 2: JP-A-09-147146).
The apparatus disclosed in Patent Literature 1 captures an image of a cross section of a three-dimensional object using an X-ray CT scanner and calculates a difference between the captured image and the design data. The apparatus disclosed in Patent Literature 2 uses an MRI to inspect a cross section of the formed three-dimensional object.
However, the cross-section inspection using the X-ray CT scanner or MRI disclosed in the above Patent Literatures 1 and 2 requires an expensive and large-sized apparatus. Further, when X-ray and the like are used, such an inspection entails a problem in terms of safety.